#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 2e5;
int n, q, s, t, arr[N + 5], tree[4*N + 5];
void update(int v, int tl, int tr, int k, int x) {
if (tl == tr) tree[v] += x;
else {
int tm = (tl + tr)/2;
if (k <= tm) update(v*2, tl, tm, k, x);
else update(v*2 + 1, tm + 1, tr, k, x);
tree[v] = tree[v*2] + tree[v*2 + 1];
}
}
int query(int v, int tl, int tr, int l, int r) {
if (l > r) return 0;
else if (tl == l && tr == r) return tree[v];
else {
int tm = (tl + tr)/2;
return query(v*2, tl, tm, l, min(tm, r)) + query(v*2 + 1, tm + 1, tr, max(l, tm + 1), r);
}
}
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> q >> s >> t;
for (int i = 0; i <= n; i++) {
cin >> arr[i];
update(1, 0, n + 1, i, arr[i]);
update(1, 0, n + 1, i + 1, -arr[i]);
}
int ans = 0;
for (int i = 0; i < n; i++) {
if (arr[i] < arr[i + 1]) ans -= s*abs(arr[i] - arr[i + 1]);
else ans += t*abs(arr[i] - arr[i + 1]);
}
while (q--) {
int l, r, x;
cin >> l >> r >> x;
int pl = query(1, 0, n + 1, 0, l - 1), curl = query(1, 0, n + 1, 0, l);
if (pl < curl) ans += s*abs(pl - curl);
else ans -= t*abs(pl - curl);
int nr = query(1, 0, n + 1, 0, r + 1), curr = query(1, 0, n + 1, 0, r);
if (r < n && curr < nr) ans += s*abs(nr - curr);
else if (r < n) ans -= t*abs(nr - curr);
update(1, 0, n + 1, l, x);
update(1, 0, n + 1, r + 1, -x);
curl += x;
if (pl < curl) ans -= s*abs(pl - curl);
else ans += t*abs(pl - curl);
curr += x;
if (r < n && curr < nr) ans -= s*abs(curr - nr);
else if (r < n) ans += t*abs(curr - nr);
cout << ans << '\n';
}
return 0;
}
